By: Dr. Solomon Chollom, Virologist/ Medical Laboratory Scientist 

Commentaries on the Pfizer vaccines ordered by the federal government of Nigeria have continued to dominate discussions amongst experts in Nigeria. Some experts have expressed fear that Nigeria lacks logistics infrastructure to store and transport those vaccines at the appropriate temperatures, some have questioned the shelf life of the vaccine while others have raised concerns around similarity or otherwise of SARS-CoV-2 variants used in manufacturing vaccines and those circulating in Nigeria, thereby questioning its effectiveness when deployed for use. 

It is therefore important for the public to know that going by available information on the vaccine as provided by Pfizer regarding logistics of the vaccines, Nigerians may not need to worry.

According to the information, the Pfizer vaccines will be delivered in thermal shippers and countries have three options for logistics:

The first option is to store these vaccines in ultra-low temperature freezers. These are -80 degree freezers and the vaccines will be viable for up to six months. 

The second option is to use the thermal shippers in which the vaccine doses arrive as temporary storage units. All that is required is for the units to be re-filled with dry ice at five day intervals. This way, the vaccine stays viable for up to 30 days

The third option is to use 2-8 degree refrigerators once a vaccine has been thawed from the thermal shippers. Once thawed at maintained at this temperature, it can stay viable for up to 5 days. This is in addition to the 30 days it must have stayed in thermal shippers. 

With this, we can organize our vaccines logistics in this manner: The -80 degrees freezers in vaccine cold rooms at state capitals can serve as state depots for the vaccines. At this temperature, vaccines remain viable for up to six months

Then we use the thermal shippers that came with these vaccines as conveyor units to move vaccines from the state depot to vaccination centres (these could either be tertiary, secondary or primary health centres) since the vaccines can stay viable in the thermal shippers for up to 30 days provided we have changes of dry ice at 5 days intervals, this way we reach the remote areas. The good thing is that we can have -80 degree freezers in some of these health centres and so storage in these areas will not be a problem. That means vaccines can be stored at -80 degree Celsius in these sub- regional centres 6months shelf life maintained

At the vaccination points, we will designate 2-8 degree refrigerators for use once vaccines are thawed from thermal shippers. At these temperatures, the vaccines will stay viable for 5 days. With adequate planning, once thawed, vials of vaccines should be exhausted same day without a need to store any further.

The good thing is that in this first instalment, Nigeria has not requested for so many doses. Just about 100,000 vials which should go for 50,000 people since each person is expected to take two shots. In this arrangement, the target group is the frontline health workers and high profile authorities. These groups can easily be mapped and organised to designated centres without much logistics challenges to warrant extended days of waiting. So no delays are envisaged here. Once vaccination centres have been mapped out and number of people to be vaccinated identified and communicated, once vaccines are thawed, they should be used same day.

All that government needs to do is to ensure there is constant power supply at the state depots to power the freezers and dry ice making machines, training and motivation of vaccinators. This way, Covid-19 vaccines will be administered without hitches.

However, concerns around the similarity or otherwise of SARS-CoV-2 variants used in manufacturing vaccines and those circulating in Nigeria are what laboratory-based research can confirm. To do this, we need to know the strains of the virus circulating in Nigeria and those used to manufacture the vaccines. This way, we would know if the antigens match or not.

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